<?php
/**
 * How busy each day and time window is.
 *
 * One SQL query reads date / time / mode of all counted orders in the booking window and the
 * result is cached in a transient. The cache is dropped only when an order, a calendar entry
 * or the settings change — not on every page view.
 */

defined( 'ABSPATH' ) || exit;

define( 'DAYSLOT_OCC_CACHE', 'dayslot_occupancy' );

/**
 * Raw bookings between two dates: array of array( id, date, slot, mode, location, status, kind ).
 * Add-ons add their own rows (calendar entries, external calendars) via `dayslot_occupancy_rows`.
 */
function dayslot_booking_rows( $start, $end, $statuses = null ) {
	global $wpdb;
	if ( null === $statuses ) {
		$statuses = (array) dayslot_get_settings()['statuses'];
	}
	$rows = array();
	if ( $statuses ) {
		$hpos   = class_exists( \Automattic\WooCommerce\Utilities\OrderUtil::class ) && \Automattic\WooCommerce\Utilities\OrderUtil::custom_orders_table_usage_is_enabled();
		$wanted = array_flip(
			array_map(
				function ( $s ) {
					return 'wc-' . sanitize_key( $s );
				},
				$statuses
			)
		);
		// Statuses are filtered below in PHP, so the query has a fixed number of placeholders.
		if ( $hpos ) {
			$result = $wpdb->get_results( // phpcs:ignore WordPress.DB.DirectDatabaseQuery -- one light query, cached by the caller.
				$wpdb->prepare(
					'SELECT o.id AS id, o.status AS status, d.meta_value AS date, s.meta_value AS slot, m.meta_value AS mode, l.meta_value AS location, v.meta_value AS variant
					FROM %i o
					INNER JOIN %i d ON d.order_id = o.id AND d.meta_key = %s
					LEFT JOIN %i s ON s.order_id = o.id AND s.meta_key = %s
					LEFT JOIN %i m ON m.order_id = o.id AND m.meta_key = %s
					LEFT JOIN %i l ON l.order_id = o.id AND l.meta_key = %s
					LEFT JOIN %i v ON v.order_id = o.id AND v.meta_key = %s
					WHERE o.type = %s AND d.meta_value BETWEEN %s AND %s',
					$wpdb->prefix . 'wc_orders',
					$wpdb->prefix . 'wc_orders_meta',
					DAYSLOT_META,
					$wpdb->prefix . 'wc_orders_meta',
					DAYSLOT_SLOT_META,
					$wpdb->prefix . 'wc_orders_meta',
					DAYSLOT_MODE_META,
					$wpdb->prefix . 'wc_orders_meta',
					DAYSLOT_LOCATION_META,
					$wpdb->prefix . 'wc_orders_meta',
					DAYSLOT_VARIANT_META,
					'shop_order',
					$start,
					$end
				),
				ARRAY_A
			);
		} else {
			$result = $wpdb->get_results( // phpcs:ignore WordPress.DB.DirectDatabaseQuery -- one light query, cached by the caller.
				$wpdb->prepare(
					'SELECT p.ID AS id, p.post_status AS status, d.meta_value AS date, s.meta_value AS slot, m.meta_value AS mode, l.meta_value AS location, v.meta_value AS variant
					FROM %i p
					INNER JOIN %i d ON d.post_id = p.ID AND d.meta_key = %s
					LEFT JOIN %i s ON s.post_id = p.ID AND s.meta_key = %s
					LEFT JOIN %i m ON m.post_id = p.ID AND m.meta_key = %s
					LEFT JOIN %i l ON l.post_id = p.ID AND l.meta_key = %s
					LEFT JOIN %i v ON v.post_id = p.ID AND v.meta_key = %s
					WHERE p.post_type = %s AND d.meta_value BETWEEN %s AND %s',
					$wpdb->posts,
					$wpdb->postmeta,
					DAYSLOT_META,
					$wpdb->postmeta,
					DAYSLOT_SLOT_META,
					$wpdb->postmeta,
					DAYSLOT_MODE_META,
					$wpdb->postmeta,
					DAYSLOT_LOCATION_META,
					$wpdb->postmeta,
					DAYSLOT_VARIANT_META,
					'shop_order',
					$start,
					$end
				),
				ARRAY_A
			);
		}
		foreach ( (array) $result as $row ) {
			if ( ! isset( $wanted[ $row['status'] ] ) ) {
				continue;
			}
			$rows[] = array(
				'kind'     => 'order',
				'id'       => (int) $row['id'],
				'date'     => (string) $row['date'],
				'slot'     => (string) $row['slot'],
				'mode'     => 'pickup' === $row['mode'] ? 'pickup' : 'delivery',
				'location' => (string) $row['location'],
				'variant'  => (string) $row['variant'],
				'status'   => substr( (string) $row['status'], 3 ),
			);
		}
	}
	return apply_filters( 'dayslot_occupancy_rows', $rows, $start, $end );
}

/**
 * Pool of a booking row.
 */
function dayslot_row_pool( $row ) {
	return dayslot_pool_key( $row );
}

/**
 * Turn rows into counts: array( date => array( pool => array( 'total' => n, 'slots' => array( key => n ) ) ) ).
 */
function dayslot_aggregate_rows( $rows ) {
	$out = array();
	foreach ( $rows as $row ) {
		if ( ! empty( $row['no_count'] ) ) {
			continue;
		}
		$date = $row['date'];
		$pool = dayslot_row_pool( $row );
		if ( ! isset( $out[ $date ][ $pool ] ) ) {
			$out[ $date ][ $pool ] = array(
				'total' => 0,
				'slots' => array(),
			);
		}
		if ( empty( $row['no_total'] ) ) {
			++$out[ $date ][ $pool ]['total'];
		}
		if ( $row['slot'] ) {
			foreach ( dayslot_capacity_keys( $row['slot'], isset( $row['variant'] ) ? $row['variant'] : '' ) as $key ) {
				$out[ $date ][ $pool ]['slots'][ $key ] = ( isset( $out[ $date ][ $pool ]['slots'][ $key ] ) ? $out[ $date ][ $pool ]['slots'][ $key ] : 0 ) + 1;
			}
		}
	}
	return $out;
}

/**
 * Booking window kept in the cache.
 */
function dayslot_occupancy_window() {
	$today = dayslot_today();
	return array(
		$today->modify( '-1 day' )->format( 'Y-m-d' ),
		$today->modify( '+' . ( (int) dayslot_get_settings()['max_days'] + 1 ) . ' days' )->format( 'Y-m-d' ),
	);
}

/**
 * Cached counts for the whole booking window.
 */
function dayslot_occupancy_all() {
	global $dayslot_occ_memo;
	if ( null !== $dayslot_occ_memo ) {
		return $dayslot_occ_memo;
	}
	list( $start, $end ) = dayslot_occupancy_window();
	$cached              = get_transient( DAYSLOT_OCC_CACHE );
	if ( is_array( $cached ) && isset( $cached['start'], $cached['end'], $cached['data'] ) && $cached['start'] === $start && $cached['end'] === $end ) {
		$dayslot_occ_memo = $cached['data'];
		return $dayslot_occ_memo;
	}
	$dayslot_occ_memo = dayslot_aggregate_rows( dayslot_booking_rows( $start, $end ) );
	set_transient(
		DAYSLOT_OCC_CACHE,
		array(
			'start' => $start,
			'end'   => $end,
			'data'  => $dayslot_occ_memo,
		),
		12 * HOUR_IN_SECONDS
	);
	return $dayslot_occ_memo;
}

/**
 * Forget the cached counts (called whenever bookings change).
 */
function dayslot_flush_occupancy() {
	global $dayslot_occ_memo;
	$dayslot_occ_memo = null;
	delete_transient( DAYSLOT_OCC_CACHE );
	do_action( 'dayslot_occupancy_flushed' );
}

/**
 * Counts for one date and the context's pool: array( 'total' => n, 'slots' => array( key => n ) ).
 * When rescheduling, the order itself is not counted.
 */
function dayslot_occupancy( $date, $ctx = array() ) {
	$ctx                 = dayslot_ctx( $ctx );
	list( $start, $end ) = dayslot_occupancy_window();
	if ( $date >= $start && $date <= $end ) {
		$all = dayslot_occupancy_all();
	} else {
		$all = dayslot_aggregate_rows( dayslot_booking_rows( $date, $date ) );
	}
	$pool = dayslot_pool_key( $ctx );
	$occ  = isset( $all[ $date ][ $pool ] ) ? $all[ $date ][ $pool ] : array(
		'total' => 0,
		'slots' => array(),
	);

	if ( $ctx['exclude_order'] ) {
		$order = wc_get_order( $ctx['exclude_order'] );
		if ( $order && $order->get_meta( DAYSLOT_META ) === $date && in_array( $order->get_status(), (array) dayslot_get_settings()['statuses'], true ) ) {
			$c = dayslot_order_choice( $order );
			if ( dayslot_pool_key( dayslot_ctx_for_choice( $c ) ) === $pool ) {
				$occ['total'] = max( 0, $occ['total'] - 1 );
				foreach ( $c['slot'] ? dayslot_capacity_keys( $c['slot'], $c['variant'] ) : array() as $key ) {
					if ( isset( $occ['slots'][ $key ] ) ) {
						$occ['slots'][ $key ] = max( 0, $occ['slots'][ $key ] - 1 );
					}
				}
			}
		}
	}
	return $occ;
}

// --------------------------------------------------------------------------
// Cache invalidation
// --------------------------------------------------------------------------

foreach ( array( 'woocommerce_new_order', 'woocommerce_update_order', 'woocommerce_order_status_changed', 'woocommerce_delete_order', 'woocommerce_trash_order', 'woocommerce_untrash_order', 'dayslot_order_values_saved' ) as $dayslot_hook ) {
	add_action( $dayslot_hook, 'dayslot_flush_occupancy' );
}
unset( $dayslot_hook );

add_action( 'update_option_dayslot_settings', 'dayslot_flush_occupancy' );

// Legacy (post-based) order storage.
add_action(
	'clean_post_cache',
	function ( $post_id, $post ) {
		if ( $post && 'shop_order' === $post->post_type ) {
			dayslot_flush_occupancy();
		}
	},
	10,
	2
);